Crystalline/amorphous hetero-phase Ru nanoclusters for efficient electrocatalytic oxygen reduction and hydrogen evolution

Abstract

The development of excellent catalysts via interface engineering has been intensively explored due to its great potential for enhancing the electrocatalytic performance. However, the hetero-phase interface composed of the same species as advanced electrocatalysts is seldom reported. Herein, a novel hetero-phase structure strategy involving amorphous and crystalline phases is developed to construct Ru nanoclusters on nitrogen-doped carbon nanosheets via ion adsorption and subsequent heat treatment, which contain abundant interfaces formed by a crystalline phase and an amorphous phase (Ru/nitrogen-doped graphene(N-G)). Significantly, the as-prepared Ru/N-G-500 shows excellent activity towards the oxygen reduction reaction (ORR) with a half-wave potential (E_1/2) of 0.847 V. Furthermore, Ru/N-G-500 also exhibits a low onset potential of about 0 mV and an overpotential of 20.1 mV at 10 mA cm⁻² in HER. The catalytic performance of Ru/N-G-500 is optimal compared with the corresponding reference samples Ru/N-G-300 (mainly exists in amorphous states) and Ru/N-G-700 (exists in crystalline states). The excellent catalytic performance can be attributed to the presence of a high density of the crystalline and amorphous phase interface on the highly dispersed Ru nanoclusters, which optimizes the intermediate adsorption and promotes electron transport. This work provides a novel strategy to design and develop efficient electrocatalysts by phase interface engineering.